Electrode wire advance for arc welding

ABSTRACT

An electrode wire advance for arc welding utilizes an electrode wire supplied through a flexible hose and acted upon by two drives. One wire drive pushes or unwinds the wire and is connected thereto by a coupling. The other wire drive pulls the wire from its hose and pushes it to the torch.

United States Patent [72] Inventor Gunter Wilkem Kelkheim/Tnuuus,Germany [21 1 App]. No. 816,984

[221 Filed Apr. 17, 1969 [45] Patented Dec. 28, 1971 [73] AssigneeMeseer Grielhelm Gmbil Frankfurt am Main, Germany [32] Priority Apr. 10,1969 [3 3] Germany [54] ELECTRODE WIRE ADVANCE FOR ARC PrimaryExaminerRichard A. Schacher AttorneyConnolly and Hutz ABSTRACT: Anelectrode wire advance for arc welding util- WELDING izes an electrodewire supplied through a flexible hose and 5 Claim" 5 Drum! acted upon bytwo drives. One wire drive pushes or unwinds [52] U.S. Cl 226/108, hewire and is connected thereto by a coupling. The other 314/69 wire drivepulls the wire from its hose and pushes it to the [51] Int. Cl. B65h17/20 torch- 79 A cr 3.; 70 ,L'f 30 1 I Pa te nte d DeC. 28,v 1971 '3Shoots-Shoot 1 v Patented Dec. 28; 1971 Sheets-Shoot Patented Dec. 28,1971 3 Sheets-Shoot I5 VT, ZV H ELECTRODE WIRE ADVANCE FOR ARC WELDINGBACKGROUND OF INVENTION This invention relates to an electrode wireadvance for arc welding wherein the electrode wire is supplied to theapparatus through a flexible hose and wherein two drives act on theelectrode wire, of which one unwinds the wire from the storage reel andleads into the flexible hose and the other pushes the wire to the arc.

The object of the invention is to avoid cracking or rolling of the wire,disadvantages which set in particularly in long, flexible wireconduction hoses. According to the German Pat. No. 1,099,666 it hasalready been tried to solve this problem in that the first (pushing)wire drive was driven by a controlled motor and determined by the speedof the wire supply; and the second wire drive conducted the wire,pulling under slippage, where in starting, conducting and stopping ofthe wire advance, the wire was always kept under a light tension. Inorder to materialize this thought, it is required, however, to choosefor the pulling drive a motor with a soft characteristic (increasing thepulling force with decreasing the wire speed as a result of increasingfrictional resistance), while the pushing drive must be provided with amotor with a stronger characteristic. In starting, the wire is pushedimmediately by the rear drive with full pushing force into the hose,while at the front drive-in accordance with the weak characteristic ofthe pulling motor-the full tractive force is not yet available. Theresult is a wire rolling which--if' it remains in the flexiblerangeleads to a jerky emergence of the wire from the hose. In plasticwire forming, the wire emerges from the hose in rolling form so that itno longer can be introduced into the torch nozzle.

SUMMARY OF INVENTION According to the invention, these disadvantages areavoided in that the pulling drive is connected with the wire by pressingupon it on both sides and the pushing drive by a coupling which preventsexceeding of a predetermined pushing force on the wire.

By such a limitation of the pushing force on the wire, it is possiblewithout difficulty to avoid the danger of a rippling of the wireexisting particularly in the starting procedure. In order to utilize tothe utmost, the generated power of the pushing force corresponds to thebuckling load of the wire. As the coupling or slip clutch, a slippingcoupling, known per se, is suitably chosen whose slip-through momentumcan be adjusted. In view of an optimum utilization of the pushing drive,it is recommended furthermore to have such a design of the coupling thatthe pushing force of the pushing drive on the wire during theslip-through of the coupling corresponds to the buckling load of thewire. This can be achieved by an abrasive coating with a low coefficientof friction.

A ripping of the wire should not be feared, since the pressure of thefront driving roller on the wire can be adjusted in such a manner thatthey slip through if. the resistance force of the wire or the pull ofthe traction drive becomes too great. As for the rest, an increase ofthe pull with lowering of the rate of revolutions of the motor(reduction of the wire advance) can be easily avoided by means of anessentially constant characteristic of both drives, predominantly of thepulling drive.

THE DRAWINGS The invention is described in more detail by way of theexemplified embodiments in the drawing and the disclosure below.

FIG. 1 shows (schematically perspective wire drive for the protectivegas welding with melting off electrode;

FIG. 2 shows (schematically) another design of a wire drive;

FIG. 3 shows the pushing station of the wire drive according to FIGS. 1and 2;

FIG. 4 shows a welding torch with built-in pulling station according tothe design of FIG. 2; and

FIG. 5 shows a slipping coupling in the pushing station according toFIGS. 1 and 2.

DETAILED DESCRIPTION In the wire drive according to FIG. 1, the weldingwire is designated with 10, the roller or reel, from which it isunwound, is designated with 11, and the welding torch with 12. Fordriving the wire 10, there are provided a pushing station 13 and ispulling station 14. Between pushing station 13 and pulling station 14there extends the wire guide hose, which for simplification purposes isnot illustrated in FIGS. 1 and 2. The pushing station 13 unwinds thewire from the roller 11 and pushes it into the wire guiding hose, whilethe pulling station 14 pulls the wire from the hose and conducts it tothe torch 12. The transmission of the driving force to the wire 10 takesplace, with respect to pushing station 13 as well as pulling station 14,by means ofa pair of rollers 15, 16 or 17, 18.

The pushing station 13, which in FIG. 3 is again illustrated in all itsparticulars, consists of a boxlike case 20 provided with a handle 19wherein is situated the actual pushing drive, described in more detailbelow. Within case 20 there are further arranged terminals 21 and 22respectively for the coolant inlet and outlet conduits 23, 24, theprotective gas conduit 25 and the control conduit 26, respectively.Regulating button 27 regulates the rate of revolutions of a drivingmotor 28.

The driving motor 28 is indicated by dotted lines in FIGS. 1-3 andrepresents a motor with stationary characteristic, preferably a directcurrent shunt wound electric motor. However, a frequency-controlledsynchronous or asynchronous motor may also be used with electronic ormechanical control.

The pushing drive of the wire proceeds in particular as follows: Wire 10reaches through a nozzle 29 between the rollers 15, I6. Rollers l5, 16,both of which are driven, press upon the wire at both sides and thusproduce connection with them. In other words by pressing upon the wirethe rollers produce a tensional force connection with the wire. Thedrive of the rollers 15, 16 comes from motor 28 over a gearing 30 bymeans of a slipping coupling 31, which in FIG. 5 is illustratedindividually. The drive shaft 32 in FIG. 5 is indicated by dotted lines.Shaft 32 drives by means of a nonillustrated adjusting spring or thelike a casing part 33, which is mounted on the drive shaft by means of ascrew 34. The casing part 33 is stationarily connected with a couplingdisk 36 by means of an adjusting spring 35. The coupling disk 36 isarranged axially slidable on the adjusting spring 35 and is pressedagainst a friction disk 40 by a disk- 37 and cup springs 38 whoseinitial stress is adjustable by a nut 39. The friction disk 40 in turnis engaged with the actual wire driving rollers 15 and 16 which aresupported turnably on a bushing 41 opposite the casing part 33'. Asynchronization of rollers 15, 16 occurs by way of friction disk 40 andthus is dependent on the initial stress of springs 38. The initialstress of springs 38 is suitably so chosen that the coupling slips uponreaching the buckling load of the welding wire. If a friction disk withrelatively low coefficient of friction is employed, the rotationmomentum transmitted in the slipping of the coupling remains about equalto the limiting moment of rotation shortly before the slipping.

The pull station 14 corresponds, regarding the drive, choice of thedriving motor, etc., tothe above-described pushing station 13 andtherefore this needs no further explanation. The difference as comparedto the pushing station is only in that the rollers 17, 18 are driven notby way of a slipping coupling slip clutch but directly by the gearing30. Thus the wire engaging rollers are driven directly by its drive at aconstant speed in that no slip clutch is provided therefor.

In the design of FIGS. 2 and 4, the pushing station corresponds to thedesign of FIGS. 1 and 3. The pulling station 42, however, is arrangeddirectly within the welding torch 43. The driving rollers numbered 17a,18a are driven by a motor 44 which is arranged inside the torch handle45. The design of FIGS. 2 and 4 is particularly suited for short hoselengths. However, if the design of FIG. 1 is combined with a torchaccording to FIGS. 2 and 4, a welding at a considerable distance fromthe position of the current source is possible. The pulling station 14functions in this connection partially as pushing station, while thepulling station 42 within the torch, irrespective of the supply of thewire to the torch nozzle 46 comes up to an exclusive pulling function.

I claim:

1. An arc-welding apparatus comprising an arc-welding torch, a wirestorage reel with a wire electrode thereon, a wire advance devicebetween said arc-welding torch and said storage reel, said wire advancedevice including a flexible hose, a first advance means between saidstorage reel and said hose for pulling the wire from said storage reeland pushing it into said hose, said first advance means including atleast one slip means, said slip means being a slip clutch, and secondadvance means between said hose and said torch for pulling the wire outof said hose and pushing it into said torch, said second advance meanscomprising wire engaging means and vance means includes a direct currentshunt wound electric motor.

5. An apparatus as set forth in claim 4, wherein said second advancemeans is mounted in said torch.

ill I! II II I

1. An arc-welding apparatus comprising an arc-welding torch, a wirestorage reel with a wire electrode thereon, a wire advance devicebetween said arc-welding torch and said storage reel, said wire advancedevice including a flexible hose, a first advance means between saidstorage reel and said hose for pulling the wire from said storage reeland pushing it into said hose, said first advance means including atleast one slip means, said slip means being a slip clutch, and secondadvance means between said hose and said torch for pulling the wire outof said hose and pushing it into said torch, said second advance meanscomprising wire engaging means and drive means, and said wire engagingmeans being driven by said drive means at a constant speed.
 2. Anapparatus as set forth in claim 1, wherein said first advance means hasa pushing force during the slippage of the clutch which is not greaterthan the buckling load of the wire.
 3. An apparatus as set forth inclaim 2, wherein said second advance means includes rollers drivendirectly by gear means without the inclusion of a slip clutch.
 4. Anapparatus as set forth in claim 3, wherein said first advance meansincludes a direct current shunt wound electric motor.
 5. An apparatus asset forth in claim 4, wherein said second advance means is mounted insaid torch.